Bag sealing apparatus



April 9, 1968 3,376,690

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Unite States Patent 3,376,690 BAG SEALING APPARATUS Gus G. .Iianas, 2533 Southwest Blvd., Kansas City, Mo. 64108 Filed Apr. 9, 1965, Ser. No. 446,348 9 Claims. (Cl. 53-112) ABSTRACT F THE DISCLOSURE The open end of a heat sealable bag is sleeved over a forming member. The forming member is provided with an end to end passageway, the outer end of which is in communication with a chamber formed between two jaws which have deformable portions clamping the bag tightly to and around the forming member. A vacuum pump is connected with the chamber and as the vacuum is imposed, air is evacuated from the chamber and from the bag, the negative pressure within the chamber assisting the clamping action of the jaws around the forming member. Means are provided for ushing the bag with an inert gas and for hermetically sealing the air evacuated, purged bag.

This invention deals generally with the packaging of materials in exible bag-like containers and refers more particularly to improved apparatus for evacuating air or other gases from the container (and if desired, purging the interior of the container with insert gas) and maintaining a desired internal condition in the container during the application thereto of the hermetic seal.

As indicated in such U.S. patents as Moore 3,150,472, Piazze et al. 2,984,255, Bower 2,672,268, and Rockland et al. 2,875,070, the withdrawing or" air from and hermetic sealing of iiexible bag-like containers has been dealt with in various ways. In addition, patents such as Moore 2,863,267 teach the principle of evacuating air from such a container and then injecting an inert gas.

The principal problems which are encountered in this art in general are (1) Achieving and maintaining a suciently tight seal around the bag opening during evacuation to insure of a high percentage of air exhaustion without the provision of complex and expensive equipment;

(2) Limiting the quantity of inert gas required to a volume suiiiciently low as to make the process effective economically;

(3) Facilitating manipulation of the bags, particularly with reference to properly positioning same for the evacuation and iinal closing or sealing steps.

In my invention the foregoing problems are all dealt with specifically and I have been able to obtain new results in all of the areas of interest mentioned.

A principal object of the invention is to provide apparatus of the character described wherein during evacuation the bag is clamped between cooperating jaws, which jaws are so designed that the ambient atmospheric pressure cooperates therewith to provide a substantial part of the clamping forces acting to prevent intrusion of air into the bag or the evacuation mechanism. It is a feature of my invention that by virtue of the jaw construction provided, not only is a greater percentage evacuation of air from the bag obtainable, but also I am able to obtain more rapid evacuation for a given bag volume than in many machines.

Another important object of the invention is to provide an arrangement wherein the interior of the bag can be effectively purged with an inert gas while it is held in the clamping mechanism and wherein the quantity of inert gas required to purge the interior of the bag is quite low.

A further object of the invention is to provide apparatus of the character described in which sequential evacuation and permanent sealing of the bag is achieved in rapid and facile fashion. In my invention the clamping jaws for holding the bag during evacuation and the heated jaws for effecting the closure are linked together and operated by a single power source; in addition, they are so related that the manual steps required in coupling and uncoupling the bag from the unit can be accomplished with very little danger to the operator.

Other and further objects of the invention are to provide apparatus of the character described which is simple in its construction and operation, and can be made available at relatively low cost; that is so constituted as to reduce danger to the operator to a minimum; and to achieve the additional objects and the features appurtenant thereto, appearing in the course of the following description.

In the accompanying drawings, which form a part of the specification and are to be read in conjunction therewith, and in which like reference numerals indicate like parts in the various views;

FIG. 1 is a front perspective View of a typical and preferred embodiment of the invention;

FIG. 2 is a sectional view taken generally along the line 2-2 of FIG. 1, the air, vacuum and gas lines being shown schematically;

FIG. 3 is a view similar to FIG. 2, but showing the clamping and sealing jaws in the closed position which obtains during iinal heat sealing of the bag; and

FIG. 4 represents a combination of a view taken generally along the line 4-4 of FIG. 2 in the direction of the arrows with a diagrammatic showing of the vacuum, compressed air, inert gas and electrical control systems.

Referring to the drawings, and initially to FIG. 1, the preferred embodiment of the invention comprises a unit which is adapted to be placed upon a table or bench top with the bottom of the unit approximately at waist level so that an operator when standing upright in front of it would be in a comfortable position to operate it. For illustrative purposes, I have shown the unit as having a main frame F which is supported upon front and rear legs 16 and 11. The frame F is essentially an open box-like frame having the parallel rectangular sides 12, these being preferably constructed of interconnecting lengths of angle cross section, The unit is essentially symmetrical about a vertical plane extending centrally through the unit from front to back (a plane essentially on the lines 2-2 of FIG. l), and consequently I have not shown the other side of the unit. It will be understood that basically the other side appears the same as the side seen in FIG. 1.

Supported above the frame F by a means subsequently to be described are the cooperating upper and lower clamping jaws 14 and 15 respectively. These jaws are each rectangular in plan. In the illustrated embodiment, they comprise substantially dat pieces of steel. On their confronting faces they are provided with strips of resilient gasket material .16. These strips parallel the edges and ends of the plates 14 and 15 and are unly secured thereto in such a manner as to dene confronting rectangular cavities or recesses 14a and 15a. The gasket material 16 is preferably a ctosed cell foam rubber having the qualities of low resistance to compressive deformation but good dimensional stability, i.e., resilience.

As can be appreciated by looking at FIGS. 2 and 3 in conjunction with IFIG. 1, the lower jaw 15 is carrie-d on a pair of spaced parallel horizontal members 17 form- -ing part of a parallelogram linkage including also the forward links 18, rearward links 19 and the stationary bottom members 20. It will be understood that like the upper members 17, there are pairs of front links 18 and,

Irear links 19 as well as bottom members 20 s0 that a similar arrangement of members and links is provided at each side of the machine, i.e., the ends of jaw 15. The

stationary members 20 are carried by and secured to the tops of the respective frame sides 12.

The links 18 are joined by parallel upper and lower cross rods 21 and 22, respectively, these rods being secured to and projecting beyond the outside surfaces of the links to provide the projecting portions 21a and 22a at each end of the rods on the respective opposite sides of the machine. The portions 21a, 22a are journaled in appropriate recesses formed `in the members 17 and 20. Similar upper and lower rods 23, 24, respectively, interconnect the rear links 19 of the parallelogram linkage. Link 23 has the endmost portions as at 23a (FIG. 1) which are journaled vin appropriate recesses in the under` side of the upper horizontal member 17 and the lower cross rod 24 has a similar portion at each end as at 24a (again see FIG. 1) which is journaled in the corresponding lower stationary member 20.

The upper jaw 14 is swingable toward and away from the lower jaw about a lpivot axis delined by the longitudinal axis of the rear link rod 23. A lever arm 25 is journaled on the rod 23. The upper end of this arm is connected with a member 26 which in turn is secured to the top of the upper jaw 14. It will be understood that a similar arm 25 and member 26 (not shown) are near the opposite side of the machine from that seen in FIG. 1.

The upper and lower jaws are interconnected also by means of a pair of cam plates 27, one'such plate at each end of the jaw assembly. The cam plates are secured in common to a shaft 28 extending across the upper surface of jaw 14. This shaft is journaled in spaced bearings 29 aflixed to the top of the jaw. At one end the shaft has secured thereto the hand lever 30 which, when the jaws are in the open position as illustrated in FIGS. 1 and 2, is substantially upright or inclined slightly toward the rear of the machine.

The lower portions of cam plates 27 have slots 27a therein in which are received the projecting portions 21a of the rod 21. The slot 27a is essentially straight, although it is provided at its opposed ends with oppositely facing indentations or notches 27b and 27c in the side edges. These notches serve to cooperate with rod portions 21a to releasably maintain the jaws in the open or 1closed condition, as the case may be.

Turning now to FIG. 4 in conjunction with the other figures, it will be observed that supported adjacent the upper side of the lower jaw 15 is a long thin substantially at rectangular member 31. This member is preferably constructed of metal and is of lesser strength than the overall length of the upper and lower jaws. It is carried by and extends forwardly in cantilever fashion from the upper leg of a leaf spring 32. The leaf spring is substantially V-shaped in cross section and its other leg is welded or otherwise rmly secured to the lower jaw 15 within the cavity 15a. The leaf spring 32 is so formed that the member 31 is firmly but resiliently held in slightly upwardly and forwardly inclined position with its forward end (thatend opposite the spring) spaced well above the gasket material 16 on t-he lower jaw. As can be seen in FIG. 2, the forward end of the member 31 is so located that if pressed down toward the lower jaw 15 (as is the case in FIG. 3) it will be very close to if not slightly beyond the outside edge of gasket material. The reason for this will subsequently be made clear.

The member 31 is provided with a plurality of front to rear passageways 33 which open at their opposite ends in the front and rear edge surfaces of the member 31. The passageways are parallel and preferably there are more than three, the present embodiment being shown with eight. Near the endmost edges additional passageways 34 are provided, these also having end openings in the front 'and rear edges of the member 31. The rear openings of these passageways 34 are connected respectively with lengths of exible tubing 35 which proceed to a Y which in turn is connected with a passageway 36 through the bottom jaw 15. This passageway has con- 4 nected with it a further tube 37 which leads from a source of inert gas. A valve 38 is interposed in the line 37 so that the flow of inert gas can be regulated.

A second passageway 39 is provided through the lower jaw 15 substantially at the rear center portion of the recess 15`a. With this passageway `is connected a line 40` which leads to a source of vacuum, such as a vacuum pump `(not shown). A three-way valve 41 which may be manually or electrically controlled, is interposed in vacuum line 40. The valve control means, whether manual or electric, is positioned for easy access by the operator.` A vacuum gauge D connects with line 40, and as can be seen in FIG. 1, is readily visible to the operator.

Located below a lower jaw 15 `is a sealing or die member 42 which cooperates with an upper die 43 in a manner subsequently to be described to form a line seal across the bag following the evacuation of air from it. The sealing dies are constructed of material having good heat conductivity and are heated by means of electric heater elements 44 disposed in longitudinal bores formed in the respective die members. The electrical conductors to the respective heat elements are shown at 45. A thermometer T may be included on the upper or lower die as seen in FIG. l.

In the preferred embodiment, the lower die 42 is sta- -tionary, being supported on the front top edge of frame F. The upper die 43 is carried at the rear of a pivotal arm 46 constructed in t-he form `of a rectangular frame structure having the forward cross member 46a and parallel side members 4611, only one of which is seen in `FIG.`

l. On each side of and at the rear of the arm 46- are located connector block assemblies 47 ywhich join the sides 46b of the arm to a horizontal shaft `48. The shaft 48 is in turn journaled in spaced bearings I49 supported on the rear of the frame lF, oney adjacent each side of the frame.

The upper sealing die 43 is pivoted about the axis of shaft 48 by means of an air cylinder 50 having the extending piston rod 50a. A connecting block 51 is secured to the end of piston rod 50a and this in turn is pivotally connected to a horizontal axle 51a on which is pivoted one end of a forwardly extending link 52. The other end of link 52 connects with a rod 53 extending between and secured `to the rear links 19 of the parallelogram linkage earlier described.

It will be observed that an arm 54 is also pivoted on axle 51, which arm is joined with a block assembly `55 keyed as at 56 to lthe shaft 48.

Both the arm 54 and link `52 are two-part in construcV tion. The respective parts are connected through the use of elongated slots in one which receive pins 52a and `54a respectively, to permit the necessary shortening and lengthening of the arm and link respectively during operation of the mech'an-ism.

The forward end of the air cylinder 49 is pivotally supported on a horizontal shaft 57 which is secured at its ends to vertical frame components 58 by blocks 59. A sleeve 60 secured to the end of the piston rotatably encircles the shaft and provides the pivotal support.

The control system for the air cylinder is shown schematically in FIG. 4. The piston is a single acting cylinder with the piston spring biased toward the retracted posiftion illustrated in FIG. 2. The cylinder is connected with a compressor 6'1 or other source of compressed air by a line 62 in which is interposed a two-way solenoid actuated valve l63. The valve 63 iscontained in an electric circuit comprising conductor 64, normally open lfoot switch 65, normally open safety switch 66, and return conductor 67.` Conductors 64, 67 are connected with a suitable source of electrical energy (not shown).

The foot switch 65 is a pedal or treadle type switch and is located in a position convenient to the foot of an operator for the machine when an operator is in position to operate it. The safety switch 66 which is in series with the foot operated switch comprises a microswitch body 66a (see FIG.` 1) mounted at one end of the lower jaw with the contact arm 66h of the switch positioned in the path of a pin 68I extending from the near end of the upper jaw 14. The location of the switch arm relative to the pin is such that when the jaw 14 is clamped tightly down upon jaw 15, the switch will be closed.

In preparing the m-achine for operation, the vacuum valve 41 is in its neutral position with the line 40` in communication with the atmosphere. Valve 38 in the gas line 37 is also closed. The solenoid valve 63 is in a condition wherein it shuts oi communication of pressure to the cylinder 49 so that the piston thereof is retracted. The unit is shown in FIGS. 1 and 2 as ready for reception of a bag, the evacuation of air therefrom, and sealing.

In operating the machine, a bag of the type generally indicated in the patents listed earlier is brought into position adjacent the front of the machine and its open mouth is fitted over the member 31 as indicated in FIG. 4, the ba'g being partially shown in broken lines at B. Preferably the length of the member 31 from one end sea'm to the other is just slightly less than width in the same direction of the bag, so that when fitted over the member 31 the bag is stretched, at least at its mouth portion, to substantially its fully extended wid-th. The opposed plies of the bag thus lie relatively smoothly on the opposite sides of the member 31.

When the bag is properly positioned, as described above, the operator grasps the operating handle and pulls forwardly on it. This results in bringing the upper jaw 14 down upon the lower jaw since as earlier explained, the slots 27a of the cams 27 coact with the shaft end portions 21a during rotation of the han'dle to draw the upper jaw toward the lower jaw. As the jaws close upon one another the sealing gaskets 16 will register with one lanother and will compress thus forming a tight contact seal against the outer bag surfaces and around the edges of the bags vat the ends of the member 31. Vacuum valve 4X1 is then positioned to impose a vacuum on line 40. The seal is sulhciently tight to exclude any ilow of air from outside the jaw cavities 14a, 15a, thereinto. Thus the entire vacuum imposed upon the line is transmitted to the internal chamber formed by cavities 14a, 15a, and through the passageways 33 in the member 31 to the interior of the bag. All air in ythe bag is thus quickly drawn from the bag 'through passageways I33 into the sealed chamber formed by lrecesses 14:1, 15a, and thence through port 39 into and vthrough the vacuum line 40. By observing the dial D, the operator can visually determine the vacuum being drawn and obviously can stabilize it at any point `desired by shifting valve '41 to the holld position, in which the line 40 is shut olf from both the atmosphere and vacuum source.

As earlier noted, since the handle 30 has been pulle'd to its full forward position, the indents 27b at the ends of the cam slots 27a lwill engage with the shaft portions 21a to releasably lock the jaws in 'the closed, vacuum imposing position. The operators hands are now free for subsequent operation. It is important to observe tha-t by virtue of providing the large cavities '1411, 15a which together Iform a chamber when the jaws are closed, zI am able to ob'tain advantage of atmospheric pressure in holding the jaws together. In other words, supplementing the downward pull exerted by the handle and the c'amming members 27 is an atmospheric pressure of normally 14.7 pounds per `square fo'o't. The greater the 'suction or vacuum -force on line 40, the more tightly the jaws will be forced together, thus assisting materially in obtaining an airtight se'al between the gasket sections A16.

In the event it is desired to purge or wa'sh the contents o'f the lbag with an inert gas, a charge of inert gas is delivered to the lbag by opening valve 38 in the gas line 37. The gas 'ows into the branch lines 3'5 and through the passageways l34 in member 31 into the bag. If it is de'sire'd to keep the inert 'gas in the bag, the bag can be sealed lat this point. However, if the gas is simply for washing purposes, it can then be evacuated yby closing gas valve -38 and reopening the vacuum valve 41.

When the 'bag has properly 'been evacuated and, if desired, reconditioned or purged with inert ga's, it is re'a'dy for sealing. To accomplish the sealing, the operator 'simply depresses the treadle of the foot switch 65 to close the contacts thereof. Since the closing of the bag clamping jaws 14, "15 has closed the safety Aswitch 66 by engagement of pin 68 with the arm 66b 'of the switch, a circuit is completed through the solenoid valve 63, and the valve opens communication of pressure -to the air cylinder 49. This, of course, results in extension of the piston rod 5G with the following results.

As the piston rod extends it serves to swing the arm 46 carrying the upper sealing die 43 about the axis of the shaft 48 thus closing the die 43 toward the stationary die 44. At the same time the link 52 serves to apply clockwise pivoting force Ion the rear links 19 of the parallelogram linkage to which the clamping jaws are alixed, thus shifting the clamping jaws to the right from the FIG. 2 to the FIG. 3 position. The displacement of the jaws draws the bag with them and the relationship of the parts* is such that the clamping jaws 14, 15 are retracted just far enough to permit the dies 43, 44 to come together and tightly engage the bag therebetween adjacent the forward edge of the clamping jaws. The heated die members 43, 44 serve to join the plies of the bag together to form a tight sealed closure in the usual manner.

Upon release of the foot switch 65, the circuit is broken and the spring within the cylinder 50 causes the piston to retract thus returning the parts to the FIG. 2 position. It will be understood, of course, that the jaws 14, 15 remain closed under the inuence of the vacuum still being imposed and as supplemented by the lock arrangement provided in cam slots 27a.

To release the bag from the jaws, the operator shifts vacuum valve 41 to neutral and pushes the handle 30 back toward the rear of the machine, thus rotating the cams 27 and reopening the jaws 14, 15. The bag can now be removed and another placed in the unit for evacuation and sealing.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth together with other advantages which are inherent to the structure.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

1. In apparatus for removing air or other gases from the interior of a flexible bag having an open end, the combination of a pair of clamping jaws having open and closed positions with respect to each other, said jaws having cooperating resilient sealing surfaces which define, when the jaws are closed, a chamber therebetween,

a substantially ilat, thin bag forming member carried by one of said jaws and positioned to be clamped with a bag partially sleeved thereover between said sealing surfaces, said bag forming member having an outer edge and an inner edge, the inner edge exposed to said chamber,

at least one passageway through said bag forming member having end openings respectively in said inner and outer edges, and

means for withdrawing air from said chamber,

2. In apparatus as in claim 1,

said sealing surfaces dened by confronting registering ring-like structures.

3. In apparatus as in claim 1,

a resiliently yieldable support element connecting said -bag forming member with said one jaw, said element and forming member so arranged that when said jaws are in said open position, said forming member is spaced away from each jaw and the sealing surfaces therefor.

4. In apparatus as in claim 1,

lever actuated means operable to open and close said jaws, and

releasable locking means operable automatically to lock said jaws in said closed position in response to closing thereof.

5. In apparatus as in claim 1,

a pair of heat sealing members normally positioned above and below said jaws and movable relatively toward one another to engage a bag portion therebetween,

power means for so moving said heat sealing members,

and

means operable to retract said jaw members from the path of said sealing members responsive to said power means.

6. In apparatus as in claim 3,

said support element comprising a reversely bentleaf spring, one end of which is anchored to said jaw, and the other end connected with said bag forming member.

7. In apparatus as in claim 1,`

said bag forming member having a plurality of side by side substantially parallel passageways, each open at the inner and outer edges of said member.

8. In apparatus as in claim ,'7,l

one of said passageways having connected with its opening on the inner edge a line for communicating a uid thereto,

9. In apparatus as in claim 1,

said means for withdrawing air comprising a source of vacuum and valve means operable selectively tol connect said chamber with said source and the at# mospherc.

References Cited UNITED STATES PATENTS 2,749,686 6/ 1956 Lorenz et al 53-22 2,863,267 12/1958 Moore 53`22 3,150,472 9/1964 Moore 53`22 3,255,567 6/1966 Keslar et al. 53-22 TRAVIS S. MCGEHEE, Primary Examiner. 

